title: Histone deacetylase 4 mediates SMAD family member 4 deacetylation and induces 5-fluorouracil resistance in breast cancer cells.
abstract: Histone deacetylases (HDACs) have been shown to play important roles in the regulation of chromatin remodeling by histone deacetylation, and their expression is induced in several types of cancer. In addition, they are known to be associated with resistance to anticancer drugs. However, the relevance of HDAC4 in chemoresistance remains unclear. Therefore, we investigated the interaction between HDAC4 expression and chemoresistance in breast cancer cells. We found that increased HDAC4 expression in MDA-MB-231 cells was associated with resistance to the anticancer drug 5-fluorouracil (5-FU). To verify these results, a cell line stably overexpressing HDAC4 was generated using MCF-7 cells (HDAC4OE). This cell line displayed increased 5-FU resistance, and HDAC4 knockdown in HDAC4OE cells restored 5-FU sensitivity. Consequently, we concluded that HDAC4 is a critical gene associated with 5‑FU chemoresistance. Further investigation using a microarray approach revealed that 355 genes were differentially expressed following HDAC4 overexpression. Based on functional annotation of the array results, HDAC4 overexpression was found to downregulate genes related to the transforming growth factor (TGF) β signaling pathway, including SMAD4, SMAD6, bone morphogenetic protein 6, inhibitor of DNA binding 1 and TGFβ2. We also found that HDAC4 expression regulates SMAD4 expression by inducing deacetylation of histone H3 in the SMAD4 promoter region. In addition, SMAD4 knockdown in MCF‑7 cells increased 5-FU resistance. In summary, our data suggest that HDAC4‑mediated deacetylation of the SMAD4 promoter may lead to 5-FU resistance in breast cancer cells.
authors.affiliation: Department of Pharmacology, College of Medicine, Konyang University, Daejeon 302-718, Republic of Korea.
authors.forename: Seong-Lan
authors.initials: SL
authors.lastname: Yu
authors.forename: Dong Chul
authors.initials: DC
authors.lastname: Lee
authors.forename: Ji Woong
authors.initials: JW
authors.lastname: Son
authors.forename: Chang Gyo
authors.initials: CG
authors.lastname: Park
authors.forename: Hoi Young
authors.initials: HY
authors.lastname: Lee
authors.forename: Jaeku
authors.initials: J
authors.lastname: Kang
mesh_terms: D000107:Acetylation; D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology*; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism; D049109:Cell Proliferation; D047369:Chromatin Immunoprecipitation; D019008:Drug Resistance, Neoplasm; D005260:Female; D005472:Fluorouracil / Q000494:pharmacology*; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D006655:Histone Deacetylases / Q000235:genetics / Q000378:metabolism*; D006657:Histones / Q000378:metabolism; D006801:Humans; D061986:MCF-7 Cells; D020411:Oligonucleotide Array Sequence Analysis; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D051901:Smad4 Protein / Q000235:genetics / Q000378:metabolism*; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism
chemical_list: D000964:Antimetabolites, Antineoplastic; D014408:Biomarkers, Tumor; D006657:Histones; D012333:RNA, Messenger; D012097:Repressor Proteins; C497796:SMAD4 protein, human; D051901:Smad4 Protein; D016212:Transforming Growth Factor beta; C400300:HDAC4 protein, human; D006655:Histone Deacetylases; D005472:Fluorouracil